1. Technical Field
The present disclosure relates to insufflators used in minimally invasive surgery, and in particular, the control and measurement of gas flow in insufflators.
2. Background Information
Gas insufflators have been used in the medical field for more than 30 years, primarily during minimally invasive surgery, such as laparoscopic surgery. Insufflators provide work-space for surgeons to operate within a patient's abdominal (peritoneal) cavity. The required work-space is created by delivering gas that inflates the abdominal cavity. Inflating the abdominal cavity with gas achieves what is known as pneumoperitoneum. The performance and functionality of insufflators has been evolving as more and more demands have been placed on insufflators due to increase in laparoscopic surgeries. Insufflators are now used in simple laparoscopic surgeries, such as cholecystectomy, hernia operation, and appendectomy, as well as complex laparoscopic surgeries, such as gastric bypass, lap band operations, and hysterectomy. Consequently, insufflators have had to increase their flow rates, while still maintaining acceptable pressure and flow measurement control and accuracy. The maximum flow rate capability of insufflators has increased from 9 liters per minute to 50 liters per minute and more in order to keep up with the ever increasing demands of maintaining proper pneumoperitoneum. Recently, insufflators have included pre-programmed performance ranges to account for the special needs of various surgeries, such as minimally invasive pediatric laparoscopic surgery. Pediatric laparoscopic surgery requires very low flow rates with very high accuracy and very tight range of control due to the relatively small size of the patients. Flow rates as low as 0.1 liters per minute must be controlled with accuracy tight range of control, such as plus or minus 0.03 liters per minute. There is a need for an insufflation system, apparatus, and method that meets the flow rate demands of laparoscopic surgery with acceptable accuracy and range of control to ensure patient safety.